In many medical situations, it is desirable and often necessary to implant relatively small (micro) electromechanical devices for an extended period of time. For example, it may be desirable to continually administer fluid medication (either as a gas or a liquid) to a patient over an extended period of time. Examples of such treatments included the low dose continual administration of morphine for pain control, the administration of FUDR for cancer chemotherapy, the administration of baclofen for the treatment of intractable spasticity, and the like.
In such instances, a particularly desirable goal is to maintain a relatively constant level of medication in the patient's bloodstream. In order to accomplish this goal, relatively small fluid handling devices are implanted within a patient's body. However, both the medication and bodily fluids that may contact the micro fluid handling devices are typically corrosive. Thus, it is desirable to provide a corrosion-resistant layer to at least one surface of the micro fluid-handling device to prevent or limit corrosion. For example, Saaski et al. describe that a nominal layer of a corrosion-resistant substance may be deposited on a substrate by sputtering by using an e-beam evaporator, where suitable corrosion-resistant substances may be silicon, gold, platinum, chrome, titanium, zirconium, and oxides of silicon or these metals. It is further described that oxides may be formed by thermally oxidizing the corrosion-resistant substance in air after it has been applied to the substrate. See, U.S. Pat. Nos. 5,660,728; 5,702,618; and 5,705,070 all to Saaski et al.